1. Field of the Invention
The present invention relates to a novel organopolysiloxane, a cosmetic which contains this, and a method for preparing an organopolysiloxane.
2. Description of the Related Art
In general, a secreted substance of human such as a sweat, a tear, and a sebum causes cosmetic deterioration. Especially in a make-up cosmetic, a sebum which is secreted from a skin is mixed with an oil in a cosmetic thereby excessively moistening powders in the cosmetic so that this becomes a major factor to cause cosmetic deterioration. Accordingly, in order to reduce amount of an oil in the cosmetic which is remained on a skin, a volatile oil material such as decamethyl cylcopentasiloxane has been studied as a part of the oil to be blended.
In addition, friction, water, and so forth are external factors for deterioration of cosmetic durability. Accordingly, to remedy the deterioration of cosmetic durability due to a water-soluble substance such as a sweat and a tear, or to avoid the loss of a water-soluble substance, a sedum, and so on in a skin thereby prolonging a skin protection effect, practically a silicone oil is added to enhance water-repellency. In a water-in-oil emulsion composition, to obtain freshness and good water-repellency with less stickiness, a silicone oil is used as the oil; but, in the water-in-oil emulsion which contains this silicone oil, it has been difficult to obtain an emulsion having good stability if a conventionally used emulsifier such as a polyoxyalkylene fatty acid ester is used.
Accordingly, methods wherein a polyoxyalkylene-modified organopolysiloxane (polyether-modified silicone) which has good compatibility with the silicone oil in the afore-mentioned water-in-oil emulsion is used have been proposed (Patent Documents 1 to 6). However, in the emulsion compositions like this, there still remains problems to obtain excellent emulsion stability and temporal stability; especially when this composition is used in a cosmetic, a surfactant which can secure excellent emulsion stability and temporal stability to a silicone oil and other oil materials used in a general cosmetic while keeping characteristics of these oil materials has been wanted. In addition, in the case that powders are included in a cosmetic, it is required that there will be no change such as agglomeration of powders and that the powders have excellent dispersion stability. Alternatively, a polyether-modified silicone which has a dendrimer-like branched silicone structure has been known; but structure of the dendrimer silicone part is so unique that a complicated process is necessary in its preparing process; and thus, there have been problems that not only its production cost is high but also production of a single product thereof is difficult (Patent Document 6).